StdLib/LibC/Math/w_pow.c

/* @(#)w_pow.c 5.2 93/10/01 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */
#include  <LibConfig.h>
#include  <sys/EfiCdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: w_pow.c,v 1.7 2002/05/26 22:02:02 wiz Exp $");
#endif

/*
 * wrapper pow(x,y) return x**y
 */

#include "math.h"
#include "math_private.h"


double
pow(double x, double y) /* wrapper pow */
{
#ifdef _IEEE_LIBM
  return  __ieee754_pow(x,y);
#else
  double z;
  z=__ieee754_pow(x,y);
  if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
  if(isnan(x)) {
      if(y==0.0)
          return __kernel_standard(x,y,42); /* pow(NaN,0.0) */
      else
    return z;
  }
  if(x==0.0){
      if(y==0.0)
          return __kernel_standard(x,y,20); /* pow(0.0,0.0) */
      if(finite(y)&&y<0.0)
          return __kernel_standard(x,y,23); /* pow(0.0,negative) */
      return z;
  }
  if(!finite(z)) {
      if(finite(x)&&finite(y)) {
          if(isnan(z))
              return __kernel_standard(x,y,24); /* pow neg**non-int */
          else
              return __kernel_standard(x,y,21); /* pow overflow */
      }
  }
  if(z==0.0&&finite(x)&&finite(y))
      return __kernel_standard(x,y,22); /* pow underflow */
  return z;
#endif
}